In the process of shipping one or more articles from one location to another, a packer can top-fill a container in which one or more articles have been placed with a flowable dunnage to partially or completely fill the void around the article or articles and thereby prevent or minimize any shifting movement of the objects relative to the container and/or to provide cushioning for the articles in the container.
The packer typically observes the container as it is being filled with dunnage and stops a dunnage dispenser when the container appears to be full. Some packers tend to over-fill the container, with the result that more dunnage material might have been placed in the container than is needed to adequately protect the article. At other times, a packer might under-fill the container, in which case the article might be free to move around in the container during shipment, increasing the possibility of damage. Both over-filling and under-filling typically becomes more of a problem as the speed of the dispenser increases. Currently there are void-fill dispensers, in particular paper dunnage converters, that can deliver a strip of dunnage at rates in excess of fifty feet per minute (about 0.25 meters per second).
Some attempts have been made to automate one or more aspects of the dunnage filling process to avoid or minimize these and other problems. For example, in one known system, disclosed in U.S. Pat. No. 6,527,147, a packer steps on a foot pedal to dispense air bags from an overhead supply. Using a foot pedal frees the packer's hands to distribute the air bags within the container. This system does not resolve the problems of over-filling or under-filling, however.
One solution to the over-filling and under-filling problem is provided by a system disclosed in International Application Publication No. WO 2004/041653. In this system, a probe senses the void around an article in a container, and a controller then cooperates with a dunnage converter to produce an amount of dunnage adequate to fill the void. As the dunnage is being dispensed, a packer assists in guiding and/or placing the dunnage into the container. Measuring the void volume accurately, however, is very difficult and attempting to do so adds to the complexity and expense of the system.
Rather than attempting to measure the void volume, another system described in U.S. Pat. No. 4,922,687 intentionally overfills the container and then uses blasts of air to level the dunnage before the container is closed and sealed for shipping. The excess dunnage is then recirculated for reuse. By automating the dispensing process, this system frees a packer to perform other tasks, but this system requires a recirculation system, however, which adds complexity and cost to the dispensing system.